/**
 * $RCSfile$
 * $Revision$
 * $Date$
 *
 * Copyright 2003-2006 Jive Software.
 *
 * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jivesoftware.smackx.filetransfer;

import java.io.InputStream;
import java.io.OutputStream;

import org.jivesoftware.smack.Connection;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.filter.AndFilter;
import org.jivesoftware.smack.filter.FromContainsFilter;
import org.jivesoftware.smack.filter.PacketFilter;
import org.jivesoftware.smack.filter.PacketTypeFilter;
import org.jivesoftware.smack.packet.IQ;
import org.jivesoftware.smack.packet.Packet;
import org.jivesoftware.smackx.bytestreams.ibb.InBandBytestreamManager;
import org.jivesoftware.smackx.bytestreams.ibb.InBandBytestreamRequest;
import org.jivesoftware.smackx.bytestreams.ibb.InBandBytestreamSession;
import org.jivesoftware.smackx.bytestreams.ibb.packet.Open;
import org.jivesoftware.smackx.packet.StreamInitiation;

/**
 * The In-Band Bytestream file transfer method, or IBB for short, transfers the
 * file over the same XML Stream used by XMPP. It is the fall-back mechanism in
 * case the SOCKS5 bytestream method of transferring files is not available.
 * 
 * @author Alexander Wenckus
 * @author Henning Staib
 * @see <a href="http://xmpp.org/extensions/xep-0047.html">XEP-0047: In-Band
 *      Bytestreams (IBB)</a>
 */
public class IBBTransferNegotiator extends StreamNegotiator {

	private Connection connection;

	private InBandBytestreamManager manager;

	/**
	 * The default constructor for the In-Band Bytestream Negotiator.
	 * 
	 * @param connection
	 *            The connection which this negotiator works on.
	 */
	protected IBBTransferNegotiator(Connection connection) {
		this.connection = connection;
		this.manager = InBandBytestreamManager.getByteStreamManager(connection);
	}

	public OutputStream createOutgoingStream(String streamID, String initiator,
			String target) throws XMPPException {
		InBandBytestreamSession session = this.manager.establishSession(target,
				streamID);
		session.setCloseBothStreamsEnabled(true);
		return session.getOutputStream();
	}

	public InputStream createIncomingStream(StreamInitiation initiation)
			throws XMPPException {
		/*
		 * In-Band Bytestream initiation listener must ignore next in-band
		 * bytestream request with given session ID
		 */
		this.manager.ignoreBytestreamRequestOnce(initiation.getSessionID());

		Packet streamInitiation = initiateIncomingStream(this.connection,
				initiation);
		return negotiateIncomingStream(streamInitiation);
	}

	public PacketFilter getInitiationPacketFilter(String from, String streamID) {
		/*
		 * this method is always called prior to #negotiateIncomingStream() so
		 * the In-Band Bytestream initiation listener must ignore the next
		 * In-Band Bytestream request with the given session ID
		 */
		this.manager.ignoreBytestreamRequestOnce(streamID);

		return new AndFilter(new FromContainsFilter(from),
				new IBBOpenSidFilter(streamID));
	}

	public String[] getNamespaces() {
		return new String[] { InBandBytestreamManager.NAMESPACE };
	}

	InputStream negotiateIncomingStream(Packet streamInitiation)
			throws XMPPException {
		// build In-Band Bytestream request
		InBandBytestreamRequest request = new ByteStreamRequest(this.manager,
				(Open) streamInitiation);

		// always accept the request
		InBandBytestreamSession session = request.accept();
		session.setCloseBothStreamsEnabled(true);
		return session.getInputStream();
	}

	public void cleanup() {
	}

	/**
	 * This PacketFilter accepts an incoming In-Band Bytestream open request
	 * with a specified session ID.
	 */
	private static class IBBOpenSidFilter extends PacketTypeFilter {

		private String sessionID;

		public IBBOpenSidFilter(String sessionID) {
			super(Open.class);
			if (sessionID == null) {
				throw new IllegalArgumentException("StreamID cannot be null");
			}
			this.sessionID = sessionID;
		}

		public boolean accept(Packet packet) {
			if (super.accept(packet)) {
				Open bytestream = (Open) packet;

				// packet must by of type SET and contains the given session ID
				return this.sessionID.equals(bytestream.getSessionID())
						&& IQ.Type.SET.equals(bytestream.getType());
			}
			return false;
		}
	}

	/**
	 * Derive from InBandBytestreamRequest to access protected constructor.
	 */
	private static class ByteStreamRequest extends InBandBytestreamRequest {

		private ByteStreamRequest(InBandBytestreamManager manager,
				Open byteStreamRequest) {
			super(manager, byteStreamRequest);
		}

	}

}
